On Alpha and Integrity server systems, interface to the OpenVMS
    Registry database server.

    The $REGISTRY service allows you to query, update, and set keys,
    subkeys, and values in the OpenVMS Registry database.

    The $REGISTRY service supports both asynchronous and synchronous
    operations. For asynchronous completion, use the Registry
    ($REGISTRY) system service.

    For synchronous completion, use the Registry and Wait
    ($REGISTRYW) system service. The $REGISTRYW system service is
    identical to the $REGISTRY system service, except that $REGISTRYW
    returns to the caller after the system completes the requested
    operation. For additional information about system service
    completion, see the Synchronize ($SYNCH) system service.

    This system service is 64-bit compatible.

    Format

      SYS$REGISTRY  [efn] ,func ,0 ,itmlst ,[iosb or iosa_64]

                    [,astadr or astadr_64] [,astprm or astprm_64]

                    [,timeout]

    C Prototype

      int sys$registry  (unsigned int efn, unsigned int func, void *,

                        void *itmlst, struct _iosb *iosb, ...);